WATERBURY, Vt. – The curious disappearance of a 78-year-old grandmother is now a murder mystery: A body found in the woods by two bird hunters has been identified as hers, and police on Tuesday called it a homicide.

Investigators used dental records to identify the remains of Pat O'Hagan, a vibrant widow who lived alone in Sheffield, a rural town of about 700 residents in Vermont's verdant northeastern corner that has no stores or stoplights. O'Hagan, who had nine grandchildren, was reported missing Sept. 11 after not appearing for a date with a friend to go to a rug-hooking session.

Tightlipped police investigators, who have said O'Hagan was forcibly abducted, said Tuesday they know the cause of death but won't divulge it, saying they want to preserve the integrity of the investigation.

They aren't sure where O'Hagan died, said Maj. Edward Ledo, chief of the state police's criminal investigations bureau, who announced the positive identification but wouldn't comment on the condition of the body or whether there were suspects.

"This turns the investigation into a new phase," Ledo said. "The fact that her body was found is a start, and it's a good turn."

About 250 interviews have been conducted, and they are continuing, as is analysis of crime scene evidence recovered from the wooded area in Wheelock where the body was found Sunday, about 10 miles from O'Hagan's home. Crime scene investigators were still working the scene Tuesday.

Ledo wouldn't say how long the body had been there and said police don't know whether O'Hagan died at the spot or her body was moved there.

Police have said all along there was no reason to suspect O'Hagan wandered off on her own, but they won't say what led them to conclude she'd been "forcibly removed" from her home.

Her killer or killers are on the loose, Ledo said.

"At this point in time, someone is responsible for the murder of a 78-year-old woman, and they're still at large," Ledo said. "People should take precautions, as they normally should."

O'Hagan's five adult children, who have been fixtures at police briefings about her disappearance, were absent Tuesday when Ledo gave his briefing. Ledo read a statement on their behalf in which they called it "impossible to comprehend why someone would harm her."

"Now that Pat's been found, our family's hopeful that someone will provide information that will lead to the person or persons responsible for her murder and justice will be served," he said.

O'Hagan, who moved to Vermont 15 years ago from Chelmsford, Mass., was an active member of her town, serving as president of the Sheffield Historical Society, working a church's annual chicken dinner and volunteering at a food pantry.

She sometimes camped out alone and was an active kayaker.

The news about the discovery of her body hit Sheffield residents hard.

"We're just all very sad," said 47-year-old Greg Bryant, who worked with her at the food pantry. "There's a huge hole in the community. It's a small community, and she was a big part of it."